Silencer



April 15, 1941. H. H. MAXIM ETAL SILENCER Filed Dec. 2, 1939 2Sheets-Sheet l INVENTOR HIRAM fiqmu. RM/MAXIM ATTORN EYE April 1941.HIH. MAXIM ETAL 2,238,816

SILENCER Filed Dec. 2, 1939 I 2 Sheets-Sheet 2 INVENTORfimAM/f/w/uv/v/MAn/v BY ,4440 LESLIE Em/APP ATTORN YS Patented Apr. 15,1941 UNITED STATES PATENT OFFICE SILENCER Application December 2, 1939,Serial No. 307,288

13 Claims. (Cl. 181-48) The present invention relates to muiilersparticularly designed for internal combustion engines, and hasparticular reference to installation where cooling water is passedthrough the exhaust line. A particular application of mufflers of thistype is found in silencers designed for submarines, where the use ofsalt water for cooling makes it necessary to form the silencer from castiron on account of the resistance of this material to corrosion. Byreason of the use of cast iron many of the usual features ofconstruction found in mufflers made of sheet material cannot beemployed.

It is one object of the present invention to provide a constructioncapable of being embodied in a cast iron muffler by which the acousticprinciples described in the copending application of R. B. Bourne,Serial No. 290,353, filed August 16, 1939, may be employed. A furtherobject is to provide a novel construction for causing instantaneousmixing of the cooling water with the exhaust gases and for controllingthe admission of this water. A further object is to provide a mechanicalconstruction by which a silencer of the type shown in the Maxim Patent2,093,893, September 21, 1937, may be constructed economically out ofcast iron instead of out of sheet steel as shown in that patent.Additional objects will appear from the following description andclaims.

Referring to the drawings:

Fig. 1 is a longitudinal cross-section through a mufller embodying thepresent invention;

Fig. 2 is a section on line 2-2 of Fig. 1;

Fig. 3 is a section on line 3-4 of Fig. 1;

Fig. 4 is a section on line 4-4 of Fig. 1;

Fig. 5 is a longitudinal section through one of the constructional unitsof the mufiler illustrating a modification;

Fig. 6 is an enlarged detail showing a detail of construction; a

Fig. 7 is a longitudinal section through silencer constructed inaccordance with the present invention but embodying the acousticalprinciples set forth in the Maxim Patent 2,093,893; and

Fig. 8 is a section on line 8-8 of Fig. 7.

The mufiler is formed of a series of tubular castings connected as willbe described below. In detail it comprises an inlet casting Ill,intermediate castings l|, |2, i3 and i4 and an outlet casting |5. Theseare formed as cylindrical shells having their end surfaces preferablymachined and provided with projecting annular lugs I6 (Fig. 6) enteringinto mating annular grooves I! so that adjacent sections may be heldtogether by bolts I8. Packing material Hi my be located at the bottom ofthe grooves The inlet section It includes an end header l9 and anintermediate header 20. Extending through the header I9 is a tubularmember 2| longitudinally adjustable as will be described to form a.variable annular gap 22 between its end and the intermediate header. Thewidth of the annular gap may be varied by inserting gaskets 23 ofdifferent thicknesses underneath the flange of the member 2|, thisflange being held to the header |9 as by bolts 24. The member 2| servesas the inlet connection for the silencer, the end header I9 beingconnected as by bolts 25 to a portion of the exhaust line indicated at26. In the case of a submarine silencer this portion of the exhaust lineis what is' customarily referred to as an evaporator.

The headers l9 and 20 are connected by a bridge piece 28 forming achamber into which passes a water inlet pipe 29. Water entering throughthis connection passes first into the chamber 30 within the bridgemember 28 and then through the annular slot 22 to mingle with theexhaust gases passing through the tubular member 2|. The exhaust gases,together with the water mingled with them, are then passed through acentral aperture of the header 20 into a tubular member 3| boltedthereto, this member preferably having a longitudinal slot 32 casttherein for reasons set forth in the Bourne application referred to.

The intermediate sections |2, I3 and M each comprise laterally disposedtubular conduits 33 and 34 cast therein and extending from one end ofthe casing to the other, preferably being machined flush with the endsof the sections. By reason of the packing material l8, however, themachined ends 35 of the sections do not quite touch each other and thiscauses a similar separation in the adjacent conduit sections 33 and 34.At the line of separation between the sections, therefore, the conduits33 and 34 open out into the large space 36 occurring within each of theintermediate sections. The purpose of this construction will appear morefully below.

The outlet section I5 is provided with an end header 40 and with aconduit 4| preferably provided with a longitudinal slot 42 and is openat its end adjacent the section I 4.

Disregarding for the moment the arrangement of parts to permit the useof water, it will appear that the exhaust gases enter the mufflerthrough the pipe 3| and also through the slot 32 inthe side thereof. Theend of the pipe 3| approaches, but is laterally ofiset from, the ends ofthe conduits 33 and 34; and, as is fully described in the Bourneapplication referred to above, the multiplicity of paths thus ofiered tothe exhaust gases and sound waves result in a practically completesilencing action. A similar effect occurs where the section 14 joinsonto the section [5. One or more of the sections, here shown as thesection 13, is provided with a baffle 43 to break up the direct passagefor gas otherwise afi'orded by the space 36 within the sections. Top andbottom vent and drain holes 44 and 45 in this partition permit somepassage of gas and sound, this additional passage resulting in furtherattenuation due to the fact that sound waves passing through theseopenings will reunite with the main body in a dinercut phase condition.The gaps 46 between the adjacent section conduits 33 and 34 serve toprevent any occurrence of series resonance and also provide a pluralityof possible paths for the gas and the sound waves to still furtherincrease the attenuation.

Since the silencer is intended for use with water and may be floodedduring submersion of the submarine it is necessary to provide vent anddrain openings at each end. For this reason a vent opening 41 isprovided in the end header l9 and-a vent hole 48, which may becontrolled by a valve if desired, is provided in the end header 40.Drain holes 49 and 50 are provided in the headers 19 and respectively,the conduit 4| furnishing a drain at the opposite end. Fig. 5 shows a.modification of one of the sections, here indicated at 5!. In this case,the longitudinal conduits 52 corresponding to the conduits 33 and 34 areprovided with longitudinal slots 53 which supplement the action of theperipheral slots 46 in bleeding off a portion of the gas into the twochambers 36 on either side of the baffle 43. It will be understood thatwith either form of construction the gases bled off through the gaps 46or through the slots 53 are partly led directly to the end section 15and partly led back through other such slots or gaps and again conductedalong the longitudinal conduits. The baflie 43 is preferably located atsome point which is not an integral fraction of the length of themuilier in order to avoid series resonance effects.

The silencer shown in Figs. 7 and 8 is constructed in general along thelines indicated above but the details are varied to embody theacoustical principles of the Maxim Patent 2,093,893. This silencer hasan inlet shell 60 provided with an intermediate partition 6| betweenwhich and the end Wall 62 water may be introduced through an inlet 63. Agas inlet tube 64 is longitudinally slotted at 65 and is coupled bybolts 66 to the intermediate partition. The inlet end of this conduit ispreferably flared outwardly as at 6'! and a tube 68 is secured to theend wall at 69 with intermediate packing 10 so that the width of theannular slot 1| may be varied in the manner described above.

Secured to this inlet section by a flange connection 12 of the typedescribed in connection with Fig. 6 is an intermediate section I3 havinga cast partition 14 provided with outstanding walls 15. These walls havethe form shown in Fig. 8 so that a generally kidney shaped cup 18 isformed with upper and lower open ended conduits IT and I8 respectively.

A second intermediate section 88 is provided with partition members 8|and 82 each having flanges forming cups of a shape similar to thatdescribed with relation to the cup 18. The cup 83 is spaced from the cupI6 by a gap 84 which may be formed by the spacing given by the packingmaterial in the joints 12, but which in this instance is generallyaugmented by a spacing of the partition-carried flanges from the ends ofthe sections. This is for the reason that in the device being consideredthe cups form side branches and the gaps 84 form acousticalconductivities, while in the form shown in Fig. 1 the gaps 46 betweenthe conduit sections 33 and 34 are not intended as acousticalconductivities but as leaks for sound waves and gas.

The partition 8| carries a second flange forming a cup 85, and thepartition 82 carries a flange defining a cup 86 opposed to the cup 85,both together forming a sidebranch coupled to the channel sections 11and 18 through a conductivity 8'1. The partition 82 also carries aflange defining a cup 88 opposing a cup 89 formed by flanges on apartition 90 carried in an end section 8|. This partition 90 also formsa cup 92 mating with a cup 93 formed in a partition 94, the twocombining to form a sidebranch coupled through a conductivity 95 to thelongitudinal channels. The end section 9| also carries an outlet conduit96 positioned tangent to the lower side of the silencer so as to permitdrainage. Drainage is also facilitated by vents 91, 98 and 99 performinga purpose similar to corresponding vents in the form first described.

We claim:

1. A muiiier comprising a housing, a partition therein, a plurality ofopen-ended, aligned, longitudinally spaced intermediate conduit sectionson either side of the partition, and inlet and outlet conduit sectionsat each end of the housing laterally offset from the intermediateconduit sections, said inlet and outlet conduit sections having theirportions within the housing longitudinally slotted.

2. A mufiier comprising end units, a plurality of open-endedintermediate units each having at least one open-ended conduit sectiontherein, means for coupling the sections together leaving gaps betweenthe aligned conduit sections of adjacent units, a central,longitudinally apertured inlet conduit in one of the end sections, andan eccentric, longitudinally apertured outlet conduit in the other ofthe end sections.

3. A mufller having end units, a plurality of open-ended intermediateunits each having at least one open-ended conduit section therein, meansfor coupling the units together comprising interfitting annular groovesand lugs, clamping means to hold the sections together, packing withinthe grooves of suiiicient thickness to hold the ends of the alignedconduit sections of adjacent units spaced from each other, a centrallylocated inlet conduit in one end section laterally ofiset from theintermediate conduits and longttudinally apertured, and an eccentricallylocated, longitudinally apertured outlet conduit in the other endsection.

4. A muifler having end units, a plurality of open-ended intermediateunits each having at least one open-ended conduit section therein, meansfor coupling the units together comprising interfitting annular groovesand lugs, clamping means to hold the sections together, packing withinthe grooves of suiiicient thickness to hold the ends of the alignedconduit sections of adjacent units spaced from each other, a centrallylocated inlet conduit in one end section laterally oiiset from theintermediate conduits and lon itudinally apertured, said inlet conduitalso being circumierentially apertured, a housing surrounding thecircumierentially apertured part of the inlet conduit, and means foradmitting water to said housing.

5. A munier having end units, a plurality of open-ended intermediateunits each having at least one open-ended conduit section therein, meansfor coupling the units together comprising interfltting annular groovesand lugs, clamping means to hold the sections together, packing withinthe grooves of suflicient thickness to hold the ends of the alignedconduit sections of adjacent units spaced irom. each other, a centrallylocated inlet conduit in one end section laterally offset from theintermediate conduits and longitudinally apertured, said inlet conduitbeing also circumierentially apertured, means for adjusting the width ofsaid circumferential aperture, a housing surrounding thecircumferentially apertured part of the inlet conduit, and means foradmitting water to said housing.

6. A muiiier comprising end units, a plurality of open-endedintermediate units each having at least one open-ended conduit sectiontherein with its walls spaced from the wall of the unit to provide achamber between them with its ends flush with the ends of the section,and means for coupling the units together comprising interflttingannular grooves and lugs, clamping means for holding the sectionstogether, and packing within the grooves of suflicient thickness to holdthe ends of the aligned conduit sections of adjacent units spaced onefrom another a distance corresponding to the spaces between the ends ofthe units to form an acoustic coupling between the aligned conduitsections and said chamber.

7. A muiiler comprising end units, one or more intermediate units havinga pair of diametrically opposed open-ended conduit sections castintegrally with but spaced from the walls thereof, and means forcoupling the units together leaving gaps between the aligned conduitsections of adjacent units.

8. A muffler comprising end units, a plurality of open-endedintermediate units, one or more partitions formed within each of saidintermediate sections and having flanges thereon forming at least oneopen-ended conduit section and a cup-like recess with the open side ofthe cup disposed adjacent the end of the section, and means for couplingthe units together with spaces between the aligned flanges oi adjacentunits sumcient to form an acoustical conductivity between said conduitsection and said cups.

9. A muiiier comprising end units, a plurality of open-endedintermediate units, one or more partitions carried by each intermediatesection and having flanges thereon defining at least one open-endedconduit section and cup-like recesses, the flanges of adjacent unitsbeing aligned, and means for coupling the units together comprisinginterfltting annular grooves and lugs, clamping means for holding thesections together, and packing within the grooves of suflicientthickness to hold the aligned flanges of adjacent units spaced from eachother a distance suflicient to form an acoustical conductivity betweenthe conduit sections and the sidebranches formed by adjacent recesses.

10. A muiiier comprising end units, a plurality of open-endedintermediate units, one or more partitions carried by each intermediatesection and carrying flanges defining a pair of diametrically opposedconduit sections and cup-like recesses, the flanges of adjacent unitsbeing aligned, means for coupling the units together comprisinginterfltting annular grooves and lugs, clamping means for holding thesections together, and packing within the grooves of suflicientthickness to hold the aligned flanges of adjacent units spaced from eachother a distance suflicient to form an acoustical conductivity betweenthe conduit sections and the side branches formed by adjacent recesses,a substantially centrally located inlet conduit in one end laterallyoiiset from the intermediate conduits and longitudinally apertured, saidinlet conduit being also circumferentially apertured, means foradjusting the width of said circumferential aperture, a housingsurrounding the circumferentially apertured part of the inlet conduit,and means for admitting water to said housing.

11. A muiiier comprising end units, a plurality of open-endedintermediate units, one or more partitions carried by each intermediatesection andcarrying flanges defining a pair of diametrically opposedopen-ended conduit sections and cup-like recesses, the flanges ofadjacent units being aligned, means for coupling the units togethercomprising interfitting annular grooves and lugs, clamping means forholding the sections together, and packing within the grooves ofsuflicient thickness to hold the aligned flanges of adjacent unitsspaced from each other a distance sufllcient to form an acousticalconductivity between the conduit sections and the side branches formedby adjacent recesses, a substantially centrally located inlet conduit inone end laterally offset from the intermediate conduits andlongitudinally apertured, said inlet conduit being alsocircumierentially apertured, means for adjusting the width of saidcircumferential aperture, a housing surrounding the circumferentiallyapertured part of the inlet conduit, means for admit ting water to saidhousing, and a tangentially disposed outlet conduit in the other endsection.

12. A muflier comprising end units, a plurality of open-endedintermediate units, means for coupling the units together, and anopen-ended conduit located in each intermediate section, the severalconduits being of lengths insuflicient to cause them to meet one anotherand being so positioned within their respective units as to cause themto lie in alignment one with another when the units are coupledtogether, whereby gaps will be left between the aligned conduit sectionsof adjacent units.

13. A mumer having end units, a plurality of open-ended intermediateunits, means for coupling the sections together including interflttinannular grooves and lugs and clamping means for adjacent sections, anopen-ended conduit located in each intermediate unit, the conduitsections being so positioned within theirrespective units as to causethem to lie in alignment one with another when the units are coupledtogether, and packing within the grooves, the lengths or the conduitsections being such that their ends will be held separated one fromanother by a gap determinable by the thickness of the packing in thegrooves.

HIRAM HAMILTON MAXIM. LESLIE E. KNAPP.

